TWI833084B - Patterning structure and method of manufacturing thereof - Google Patents

Abstract

A method for manufacturing a patterning structure includes the following process. A hard mask layer and a photoresist layer are sequentially stacked in a first direction. The photoresist layer is formed on the hard mask layer. An isotropic etching process is performed on the hard mask layer and the photoresist layer in a second direction perpendicular to the first direction, so that a width of the hard mask layer in the second direction is less than a width of the photoresist layer in the second direction.

Description

Patterned structures and methods of manufacturing the same

The present disclosure relates to patterned structures and methods of fabricating the patterned structures.

For the manufacturing process of semiconductor structures or semiconductor devices, patterning through masks is a very important and valued step. Especially for the formed semiconductor structure or semiconductor element, the size of the mask is closely related to the critical dimension (CD) of the semiconductor structure or semiconductor element.

How to ensure that the pattern formed by the photoresist on the mask is not damaged while ensuring that the size of the mask can be reduced is one of the problems that those skilled in the art want to solve.

One aspect of the present disclosure relates to methods of fabricating patterned structures.

According to an embodiment of the present disclosure, a method of manufacturing a patterned structure includes the following process. A hard mask layer and a photoresist layer are sequentially stacked in the first direction. A photoresist layer is formed on the hard mask layer. An isotropic etching process is performed on the hard mask layer and the photoresist layer in a second direction perpendicular to the first direction, so that the width of the hard mask layer in the second direction is smaller than the width of the photoresist layer in the second direction.

According to an embodiment of the present disclosure, in the step of sequentially stacking the hard mask layer and the photoresist layer upward, the hard mask layer and the photoresist layer are sequentially stacked and formed on the bottom layer. The material of the photoresist layer is the same as the material of the bottom layer.

According to an embodiment of the present disclosure, the method further includes patterning the hard mask through the photoresist layer.

In some embodiments, in the step of sequentially stacking the hard mask layer and the photoresist layer in the first direction, the hard mask layer and the photoresist layer are sequentially stacked and formed on the bottom layer, and the bottom layer is a semiconductor material layer. After performing the isotropic etching process, the semiconductor material layer is patterned through the pattern of the patterned hard mask layer.

According to an embodiment of the present disclosure, before performing the isotropic etching process, the photoresist layer and the hard mask layer are directly etched in the first direction to simultaneously reduce the width of the photoresist layer and the hard mask layer in the second direction. width in the second direction.

According to an embodiment of the present disclosure, the isotropic etching process uses radical compounds.

According to an embodiment of the present disclosure, after the isotropic etching process is performed, the photoresist layer completely covers the hard mask layer in the first direction.

According to an embodiment of the present disclosure, after performing an isotropic etching process, the photoresist layer has a uniform thickness in the first direction.

One aspect of the disclosure relates to a patterned structure. The photoresist layer has a uniform thickness in the first direction.

According to an embodiment of the present disclosure, a patterned structure includes a hard mask layer and a photoresist layer. The photoresist layer is stacked on the hard mask layer in the first direction. The width of the hard mask layer in the second direction is smaller than the width of the photoresist layer in the second direction, and the second direction is perpendicular to the first direction. The photoresist layer completely covers the hard mask layer in the first direction.

In one or more embodiments of the present disclosure, the photoresist layer has a uniform thickness in the first direction.

In summary, by performing isotropic etching with a high etching selectivity on the sides of the stacked hard mask layer and photoresist layer, it is possible to ensure that the hard mask is shortened without damaging the thickness and shape of the photoresist layer. The size of the layers thus helps reduce the critical dimensions of subsequently formed structures or components.

The above is only used to describe the problems to be solved by the present disclosure, the technical means to solve the problems, the effects thereof, etc. The specific details of the present disclosure will be introduced in detail in the following implementation modes and related drawings.

The following is a detailed description of the embodiments with the accompanying drawings. However, the embodiments provided are not intended to limit the scope of the present disclosure, and the description of the structural operation is not intended to limit the order of its execution. Any recombination of components The structures and devices with equal functions are all within the scope of this disclosure. In addition, the drawings are for illustrative purposes only and are not drawn to original size. To facilitate understanding, the same elements or similar elements will be designated with the same symbols in the following description.

In addition, unless otherwise noted, the terms used throughout the specification and patent application generally have their ordinary meanings when used in the field, in the disclosure and in the specific content. . Certain terms used to describe the present disclosure are discussed below or elsewhere in this specification to provide those skilled in the art with additional guidance in describing the present disclosure.

In this article, terms such as "first", "second", etc. are only used to distinguish elements or operating methods with the same technical terms, but are not intended to indicate a sequence or limit the present disclosure.

In addition, similar terms such as "includes", "includes", and "provides" are used in this article as open limitations, meaning including but not limited to.

Furthermore, in this article, unless there are special limitations on the articles in the context, "a" and "the" can generally refer to a single or multiple. It will be further understood that the terms "include", "include" and "the" used in this article "Including", "having" and similar words indicate the features, regions, integers, steps, operations, components and/or components described therein, but do not exclude one or more other features, regions, or components mentioned or added thereto. Integers, steps, operations, elements, components, and/or groups thereof.

Please refer to Picture 1 to Picture 3. 1 to 3 illustrate schematic cross-sectional views of different processes in a method of manufacturing a structure for patterning according to an embodiment of the present disclosure.

As shown in FIG. 1 , in one embodiment of the present disclosure, the patterned structure includes a stacked hard mask (HD) layer 140 and a photoresist (PR) layer 160 . In the vertical first direction D1, the hard mask layer 140 and the photoresist layer 160 are sequentially stacked on the under layer (UL) 120.

In some embodiments, the bottom layer 120 is, for example, a layer of semiconductor material, such as a layer including a silicon substrate. A hard mask layer 140 is formed on the bottom layer 120 , and then a photoresist layer 160 is formed on the hard mask layer 140 . In this way, a pattern can be formed on the hard mask layer 140 through the photoresist layer 160, and then the bottom layer 120 of the semiconductor material can be patterned through the pattern on the hard mask layer 140.

In some embodiments, the material of the bottom layer 120 is the same as the photoresist layer 160, or other photoresist materials. A hard mask layer 140 is formed on the bottom layer 120 , and then a photoresist layer 160 is formed on the hard mask layer 140 . In this way, a pattern can be formed on the hard mask layer 140 through the photoresist layer 160, and the bottom layer 120 of the photoresist material serves as an extension layer of the photoresist layer 160, and further photoresist patterns are formed through the hard mask layer 140.

For purposes of simplicity of illustration, the same or similar dimensions, lengths, widths or thicknesses are designated by the same or similar reference numerals. In FIGS. 1 to 3 , the hard mask layer 140 has a thickness T1 in the first direction D1 and a width W1 in the second direction D2, where the second direction D2 is perpendicular to the first direction D1. Similarly, the photoresist layer 160 has a thickness T2 in the first direction D1 and a width W2 in the second direction D2. In the present disclosure, the first direction D1 refers to the vertical direction of the stack, the second direction D2 refers to the direction of horizontal extension, and the second direction D2 is perpendicular to the first direction D1.

Picture 2 continues from Picture 1. In order to reduce the size of the hard mask layer 140 , a portion of the photoresist layer 160 is first removed, so that a portion of the hard mask layer 140 is exposed and not covered by the photoresist layer 160 . The hard mask layer 140 not covered by the photoresist layer 160 can be removed.

As shown in FIG. 2 , part of the photoresist layer 160 is removed, so that the width W2 of the photoresist layer 160 is reduced. Such manufacturing may be referred to as a trimming process of the photoresist layer 160 . In some embodiments, the trimming process to reduce the width W2 of the photoresist layer 160 can be implemented by plasma. Since the trimming process is implemented by plasma, as the width W2 decreases, the thickness T2 of the photoresist layer 160 will also decrease. This causes the thickness T2 of the photoresist layer 160 to deviate from the designed value.

Picture 3 continues from Picture 2. Based on the photoresist layer 160 whose width W2 is reduced after trimming, the exposed portion of the hard mask layer 140 can be removed through an etching process. In this embodiment, the portion of the hard mask layer 140 not covered by the photoresist layer 160 is removed, and the width W1 of the hard mask layer 140 is reduced to form the patterned structure 100 . Patterned structure 100 can be used to pattern bottom layer 120 .

In some embodiments, the etching of the hard mask layer 140 will also affect the photoresist layer 160 . Therefore, along with the etching of the hard mask layer 140, the photoresist layer 160 will also be eroded. Since the hard mask layer 140 is etched from the outside to the inside, the photoresist layer 160 is etched from the outside to the inside. In this way, the photoresist layer 160 will no longer be uniform, but will form a protruding hill shape, which is represented by a dotted line in FIG. 3 . This corresponds to the fact that the thickness of the effective photoresist area 165 of the photoresist layer 160 will be different for different positions in the second direction D2. This will cause the pattern on the hard mask layer 140 to deviate from the design when the hard mask layer 140 is further processed through the photoresist layer 160, resulting in a critical dimension (CD)/ IMB is unstable. When patterning is performed according to the hard mask layer 140 to form a semiconductor structure/component, it is also possible to deviate from the pre-designed patterns and critical dimensions.

Please refer to Figure 4, and refer to Figures 5 to 7 respectively according to the different processes illustrated in Figure 4. FIG. 4 illustrates a flow chart of a method 200 of manufacturing a patterned structure 300 according to an embodiment of the present disclosure. In this embodiment, the method 200 includes processes 210 to 230 . 5 to 7 illustrate schematic cross-sectional views of different processes in the method 200 of manufacturing the patterned structure 300 according to an embodiment of the present disclosure.

Please refer to Figure 4 and Figure 5 at the same time. In process 210, a hard mask layer 340 and a photoresist layer 360 are sequentially stacked in the vertical first direction D1. In this embodiment, the hard mask layer 340 and the photoresist layer 360 are sequentially formed on the bottom layer 320 .

In some embodiments, the bottom layer 320 is, for example, a layer of semiconductor material, such as a layer including a silicon substrate. A hard mask layer 340 is formed on the bottom layer 320, and then a photoresist layer 360 is formed on the hard mask layer 340. In this way, a pattern can be formed on the hard mask layer 340 through the photoresist layer 360, and then the bottom layer 320 of the semiconductor material can be patterned through the pattern on the hard mask layer 340. In some embodiments, the material of the bottom layer 320 is a photoresist material, for example, the same as the photoresist layer 360 , so that after patterning through the hard mask layer 340 , the bottom layer 320 of the photoresist material serves as an extension of the photoresist layer 360 layer, through hard mask layer 340 to form further photoresist patterns.

In FIGS. 5 to 7 , the hard mask layer 340 has a thickness T3 in a vertical first direction D1 and a width W3 in a lateral second direction D2. The second direction D2 is perpendicular to the first direction D1. Similarly, the photoresist layer 360 has a thickness T4 in the first direction D1 and a width W4 in the second direction D2.

Please go back to picture 5. In FIG. 5 , the hard mask layer 340 and the photoresist layer 360 can be formed through a deposition process, for example. Through subsequent processes of the method 200, the width W3 of the hard mask layer 340 can be reduced to a predetermined thickness, which is half or less than half of the original thickness, so that the size of the hard mask layer 340 is reduced. For example, the width W3 of the hard mask layer 340 is, for example, 40 nanometers when formed. Through subsequent processes of the method 200, the width W3 of the hard mask layer 340 can be reduced to 20 nanometers, but this does not limit the invention. Reveal. At the same time, the photoresist layer covering the reduced hard mask layer 340 The central part of the 360 may not have the problem of uneven thickness.

Please refer to Figure 4 and Figure 6 at the same time. In the optional process 220, the width W3 and the width W4 of the hard mask layer 340 and the photoresist layer 360 in the second direction D2 perpendicular to the first direction D1 are simultaneously reduced. It should be noted that at this time, the width W3 of the hard mask layer 340 has not yet been reduced to the designed final thickness. It can be understood that before reducing the hard mask layer 340 to the designed size, the outer portion of the hard mask layer 340 may be initially removed to increase the speed of the overall process.

As shown in FIG. 6 , it is designed that after the photoresist layer 360 is partially removed, the remaining thickness T4 should be sufficient to perform the subsequent process of patterning the hard mask layer 340 .

In some embodiments, etching can be provided in the first direction D1, thereby directly etching into the photoresist layer 360 and the hard mask layer 340, thereby simultaneously reducing the width W4 of the photoresist layer 360 and the hard mask layer in the second direction D2. The width of layer 340 is W3.

In some implementations, the selective process 220 can be implemented through, for example, Figure 2 and Figure 3 . Specifically, a trimming process can be performed on the photoresist layer 360 by plasma, and then the exposed outer hard mask layer 340 is removed by etching. In this way, although the outer portion of the photoresist layer 360 may have uneven thickness due to erosion (not shown), it will have less impact on the central portion of the photoresist layer 360, and it can still be ensured that the center of the photoresist layer 360 covers the hard mask layer The thickness of the 340 part is roughly uniform.

In some embodiments, the reduced width of the hard mask layer 340 can be set to be less than a predetermined value, thereby ensuring that the photoresist layer 360 is eroded Small, so that the uneven thickness of the outer edge of the photoresist layer 360 relative to the center is not obvious, ensuring that the overall thickness T4 of the photoresist layer 360 still maintains a certain degree of uniformity.

Please refer to Figure 4 and Figure 7 at the same time. In process 230 , isotropic etching 400 is performed on the hard mask layer 340 and the photoresist layer 360 in the second direction D2 so that the width W3 of the hard mask layer 340 is smaller than the width W4 of the photoresist layer 360 . That is, isotropic etching 400 is performed in the lateral direction of the stacked hard mask layer 340 and photoresist layer 360 .

The execution of the isotropic etching 400 can ensure that the thickness T3 of the hard mask layer 340 and the thickness T4 of the photoresist layer 360 are reduced uniformly in the second direction D2. In order to make the width W3 of the hard mask layer 340 smaller than the width W4 of the photoresist layer 360, the etching selectivity ratio of the isotropic etching 400 needs to be set so that the isotropic etching 400 has Etch rates vary.

Compared with Figure 6, after going through the process 230, the width W4 of the photoresist layer 360 in Figure 7 is almost the same, or only slightly reduced.

As shown in FIG. 7 , after etching, the width W3 of the hard mask layer 340 is smaller than the width W4 of the photoresist layer 360 . In some embodiments, the width W3 of the hard mask layer 340 is reduced by half compared to Figure 5 , which means that the size of the hard mask layer 340 in the second direction D2 is reduced by half.

Continuing from the uniform thickness of the photoresist layer 360 in Figure 6, in Figure 7, after lateral isotropic etching 400, the photoresist layer 360 has a uniform thickness T4 in the first direction D1. As mentioned above, since at least the thickness of the portion covering the hard mask layer 340 in the center of the photoresist layer 360 is uniform, the thickness of the photoresist layer 360 covering the hard mask layer 340 in Figure 7 will also be uniform. .

In this way, when the hard mask layer 340 is subsequently patterned through the photoresist layer 360, the effective photoresist area of the photoresist layer 360 can be Remain intact to ensure that the patterning of the hard mask layer 340 can achieve the design goals. In other words, the edge of the hard mask layer 340 will not cause defects during patterning due to the uneven thickness of the photoresist layer 360, and the side effect of the hard mask layer 340 can be improved. This enables the critical dimensions of the hard mask layer 340 to be effectively and accurately reduced.

For the isotropic etching 400 with a high etch selectivity ratio, the etch selectivity ratio of the hard mask layer 340 to the photoresist layer 360 is greater than one, so that more of the hard mask layer 340 is removed during the isotropic etching 400 .

In some embodiments, the high etching selectivity isotropic etching 400 of the process 230 can be implemented in a neutral, non-ionic (without ion) manner. For example, in some embodiments, process 230 for high etch selectivity isotropic etching 400 may be tunable to provide high etch selectivity, such as through a free radical compound. This etching method can peel off the atoms on the surface of the material layer by layer with atomic-level precision in a single layer of atoms. However, it should be understood that this disclosure does not limit the isotropic etching 400 process used in the process 230. In some embodiments, other isotropic etching techniques that can achieve high etching selectivity are also included in the present disclosure. In some embodiments, the high etch selectivity isotropic etching 400 includes a neutral, non-ionic wet etching method.

In some embodiments, the process 220 and the process 230 are etching in different directions, so different machines and equipment are used separately to increase the overall speed of the method 200 and save the time required. For example, in some embodiments, in process 220, a first machine may provide direct etching in the first direction D1 to simultaneously remove the photoresist layer 360 and the hard mask layer 340 on the bottom layer 320; subsequently, Take out the bottom layer 320, the hard mask layer 340 and the photoresist layer 360 from the first machine, and put the stacked bottom layer 320, the hard mask layer 340 and the photoresist layer 360 into another second machine with the sides facing up. stage to perform process 230 to perform an isotropic etching process.

Through the process 210 to the process 230 of the method 200, as shown in FIG. 7, the patterned structure 300 is formed on the bottom layer 320. In this embodiment, the patterned structure 300 includes a hard mask layer 340 and a photoresist layer 360. The photoresist layer 360 is stacked on the hard mask layer 340 in the first direction D1. The width W3 of the hard mask layer 340 in the second direction D2 is smaller than the width W4 of the photoresist layer 360 in the second direction D2, so that the photoresist layer 360 completely covers the hard mask layer 340 in the first direction D1. As shown in FIG. 7 , the width W4 of the bottom layer 320 in the second direction D2 is greater than the width W4 of the photoresist layer 360 in the second direction D2 .

In the case where the hard mask layer 340 is completely covered in the first direction D1 by the photoresist layer 360, in some embodiments, it is also planned to use the hard mask layer 340 with a high thickness.

As shown in FIG. 7 , the photoresist layer 360 of the patterned structure 300 has a uniform thickness T4 in the first direction D1. In some embodiments, the photoresist layer 360 has a uniform thickness at least in a central portion covering the hard mask layer 340 .

In some embodiments, the bottom layer 320 is, for example, a layer of semiconductor material that can be patterned through a reduced-size hard mask layer 340 to form a semiconductor structure or element that can have critical dimensions consistent with the design. In some embodiments, patterning of patterned semiconductor structures, such as wires or interconnect structures, is performed through the hard mask layer 340 . In some embodiments, the patterned structure 300 can be applied to the patterning process of conductors or interconnect structures in a multi-layer mask (MLR), so that the line width of the formed conductors or interconnect structures can be appropriately and accurately as designed. Shrinking, the overall key dimensions can be reduced.

In some embodiments, the bottom layer 320 can be a photoresist material, used as an extension layer of the photoresist layer 360, and used as a subsequent further photoresist after being patterned through the hard mask layer 340.

In summary, the present disclosure provides a patterned structure for patterning and a manufacturing method of the patterned structure. By performing isotropic etching with a high etching selectivity on the sides of the stacked hard mask layer and photoresist layer, it is possible to ensure that the size of the hard mask layer is shortened without destroying the thickness and shape of the photoresist layer. It is beneficial to reduce the critical dimensions of subsequently formed structures or components, or is beneficial to subsequent formation of extension layers of photoresist materials.

Although the disclosure has been disclosed in the above embodiments, it is not intended to limit the disclosure. Anyone with ordinary knowledge in the art can make various modifications and modifications without departing from the spirit and scope of the disclosure. Therefore, the disclosure The scope of protection shall be subject to the scope of the patent application attached.

100:Patterned structure

120: Bottom floor

140: Hard mask layer

160: Photoresist layer

165: Effective photoresist area

200:Method

210~230: Process

300: Patterned structure

320: Bottom floor

340: Hard mask layer

360: Photoresist layer

400: Isotropic etching

D1: Direction

D2: Direction

T1:Thickness

T2:Thickness

T3:Thickness

T4:Thickness

W1: Width

W2: Width

W3: Width

W4: Width

The advantages and drawings of the present disclosure should be better understood from the following enumerated embodiments and with reference to the accompanying drawings. The description of these drawings is merely an enumeration of embodiments, and therefore should not be considered to limit individual embodiments or limit the scope of the patentable invention. Figures 1 to 3 illustrate schematic cross-sectional views of different processes in a method of manufacturing a structure for patterning according to an embodiment of the present disclosure; 4 illustrates a flow chart of a method of manufacturing a patterned structure according to an embodiment of the present disclosure; and 5 to 7 illustrate schematic cross-sectional views of different processes in a method of manufacturing a patterned structure according to an embodiment of the present disclosure.

200:Method

210~230: Process

Claims (10)

A method of manufacturing a patterned structure, including: sequentially stacking a hard mask layer and a photoresist layer on a bottom layer in a first direction, wherein the photoresist layer is formed on the hard mask layer, the A bottom surface of the hard mask layer contacts the bottom layer; and an isotropic etching process is performed on the hard mask layer and the photoresist layer in a second direction perpendicular to the first direction, so that the hard mask layer is in A width in the second direction is smaller than a width of the photoresist layer in the second direction, wherein after the isotropic etching process is completed, a width of the bottom layer in the second direction is larger than the width of the photoresist layer the width in the second direction. The method of claim 1, wherein a material of the photoresist layer is the same as a material of the bottom layer. The method of claim 1, further comprising: patterning the hard mask layer through the photoresist layer. The method of claim 3, wherein the bottom layer is a semiconductor material layer, and after performing the isotropic etching process, the semiconductor material layer is patterned by a pattern of the patterned hard mask layer. The method of claim 1, wherein before performing the isotropic etching process, the photoresist layer and the hard mask layer are etched in the first direction to simultaneously reduce the distortion of the photoresist layer in the second direction. the width of and the hard mask The width of the cover layer in the second direction. The method of claim 1, wherein the isotropic etching process uses a free radical compound. The method of claim 1, wherein after performing the isotropic etching process, the photoresist layer completely covers the hard mask layer in the first direction. The method of claim 1, wherein after performing the isotropic etching process, the photoresist layer has a uniform thickness in the first direction. A patterned structure includes: a bottom layer; a hard mask layer stacked on the bottom layer in a first direction, wherein a bottom surface of the hard mask layer contacts the bottom layer; and a photoresist layer on the first Stacked on the hard mask layer in one direction, wherein a width of the hard mask layer in a second direction is smaller than a width of the photoresist layer in the second direction, the second direction is perpendicular to the first direction, the photoresist layer completely covers the hard mask layer in the first direction, and a width of the bottom layer in the second direction is greater than the width of the photoresist layer in the second direction. The patterned structure as claimed in claim 9, wherein the photoresist The layer has a uniform thickness in the first direction.

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